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Planck was a space observatory operated by the European Space Agency (ESA) from 2009 to 2013, which mapped the anisotropies of the cosmic microwave background (CMB) at microwave and infra-red frequencies, with high sensitivity and small angular resolution. The mission substantially improved upon observations made by the NASA Wilkinson Microwave Anisotropy Probe (WMAP). ''Planck'' provided a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure; as of 2013 it has provided the most accurate measurements of several key cosmological parameters, including the average density of ordinary matter and dark matter in the Universe. The project was started around 1996 and was initially called COBRAS/SAMBA: the Cosmic Background Radiation Anisotropy Satellite/Satellite for Measurement of Background Anisotropies. It was later renamed in honour of the German physicist Max Planck (1858–1947), who derived the formula for black-body radiation. Built at the Cannes Mandelieu Space Center by Thales Alenia Space, and created as a medium-sized mission for ESA's Horizon 2000 long-term scientific programme, ''Planck'' was launched in May 2009, reaching the Earth/Sun by July, and by February 2010 had successfully started a second all-sky survey. On 21 March 2013, the mission's first all-sky map of the cosmic microwave background was released, with an expanded release including polarization data in February 2015; final data analysis will continue into 2016. At the end of its mission ''Planck'' was put into a heliocentric orbit and passivated to prevent it from endangering any future missions. The final deactivation command was sent to ''Planck'' in October 2013. == Objectives == The mission had a wide variety of scientific aims, including:〔 * high resolution detections of both the total intensity and polarization of primordial CMB anisotropies, * creation of a catalogue of galaxy clusters through the Sunyaev–Zel'dovich effect, * observations of the gravitational lensing of the CMB, as well as the integrated Sachs–Wolfe effect, * observations of bright extragalactic radio (active galactic nuclei) and infrared (dusty galaxy) sources, * observations of the Milky Way, including the interstellar medium, distributed synchrotron emission and measurements of the Galactic magnetic field, and * studies of the Solar System, including planets, asteroids, comets and the zodiacal light. ''Planck'' has a higher resolution and sensitivity than WMAP, allowing it to probe the power spectrum of the CMB to much smaller scales (×3). It also observes in 9 frequency bands rather than WMAP's 5, with the goal of improving the astrophysical foreground models. It is expected that most ''Planck'' measurements will be limited by how well foregrounds can be subtracted, rather than by the detector performance or length of the mission, a particularly important factor for the polarization measurements. The dominant foreground radiation depends on frequency, but could include synchrotron radiation from the Milky Way at low frequencies, and dust at high frequencies. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Planck (spacecraft)」の詳細全文を読む スポンサード リンク
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